ETrade only allow direct trading on 6 foreign countries' exchanges: Canada, Japan, Hong Kong, Germany, France, UK. Trading cost is much higher than trading on US exchange, but not too bad if you buy and hold.
One concern is that the asset protection from SIPC and/or private insurance may be less robust than the protection you get in your “regular” brokerage account.
E*Trade has one of the weakest balance sheets in the online-broker space. During the financial crisis they were on the edge and look what happened to MF Global.. SIPC and FDIC insurance is limited so I use other firms.